Steam reforming is a chemical process by which a hydrocarbon feedstock reacts with steam to form a product gas mixture comprising hydrogen and carbon oxides. The reaction, which is strongly endothermic, takes place in a reactor called a reformer furnace.
The reformer furnace may typically include a tubular reaction vessel containing a steam reforming catalyst through which the reactant mixture of hydrocarbons and steam (also called: mixed-feed) is flown. The reaction vessel may be wholly or partly disposed inside a combustion chamber of the reformer furnace fitted with a number of burners that combust fuel to produce the heat necessary to sustain the endothermic reforming reaction inside the reaction vessel. Heat may be transferred to the reaction vessel by radiant heat directly from the burner flames, or by convective heat from flue gases that flow past the vessel, either co-current or counter-current to the flow of reactant mixture inside the vessel.
A notorious problem with known reformer furnaces is that both the product gas and the flue gas may exit at relatively high temperatures. In the art various reformer furnace designs have therefore been proposed to improve the overall heat economy of the reforming process by recovering the sensible heat from both the product gas and the flue gas to drive the reforming process, so as to produce additional product gas. These reformer furnace designs, however, appear to leave room for efficiency improvements. Furthermore, they may typically be relatively complex and sizeable, making them costly to construct and maintain.